Jacketed bullet

ABSTRACT

A self-lubricating, vapor trailing ammunition round including a jacket about the forward portion of the bullet and extending rearwardly about the forward portion of the casing, said jacket comprising an inner layer of plastic lubricous material with a low latent temperature of vaporization and a thin outer layer of hard, dry, frangible material. The jacket seals the annulus between the casing the the bullet. The jacket material about the casing lubricates the chamber of the fire arm on which it is engaged to prevent freezing of the casing on the chamber. A portion of the jacket material on the bullet lubricates the bore of the fire arm to extend bore life and creates an improved gas seal. A portion of the jacket remains on the bullet after it leaves the fire arm and is vaporized by friction heat between the jacket material and the air to produce a vapor trail.

baited Ettes Patent [191 Eernath Aug. 13, 1974 JACKETED BULLET JohnBernath, c/o Du-Kote Corporation, 39651 Esplanade, San Jacinto, Calif.92382 Filed: Sept. 21, 1972 Appl. No.: 290,961

Inventor:

US. Cl. 102/92, 102/38 Int. Cl. F42b 31/02 Field 05 Search 102/92,92.1-92.7,

OTHER PUBLICATIONS Organic Chemistry by E. Wertheim, 3rd Edition,McGrawI-Iill Pub. Co. 1951, p. 247. Primary ExaminerRobert F. Stahl [57] ABSTRACT A self-lubricating, vapor trailing ammunition roundincluding a jacket about the forward portion of the bullet and extendingrearwardly about the forward portion of the casing, said jacketcomprising an inner layer of plastic lubricous material with a lowlatent temperature of vaporization and a thin outer layer of hard, dry,frangible material. The jacket seals the annulus between the casing thethe bullet. The jacket material about the casing lubricates the chamberof the fire arm on which it is engaged to prevent freezing of the casingon the chamber. A portion of the jacket material on the bulletlubricates the bore of the fire arm to extend bore life and creates animproved gas seal. A portion of the jacket remains on the bullet afterit leaves the fire arm and is vaporized by friction heat between thejacket material and the air to produce a vapor trail.

10 Claims, 6 Drawing Figures IIMII'I'II",

JACKETED BULLET This invention has to do with ammunition for firearmsand is more particularly concerned with a novel jacketed bullet or ajacket like coating therefor.

In the art of firearms, ammunition comprising elongate cylindrical,metallic shells or casings with front and rear ends, ignition devices orprimers at the rear end of the casings, metal projectiles or bulletsreleasably engaged in the front ends of the casings and charges orsupplies of explosive powder in the casings between the primers and thebullets is commonly provided for use in hand guns and rifles.

The ordinary firearm, such as a rifle, in which ammunition of thecharacter referred to above is used comprises an elongate barrel withfront and rear ends, a central longitudinal bore with a plurality ofcircumferentially spaced, radially inwardly projecting andlongitudinally extending, helical rifling ribs with bulletengaginglands. The front end of the bore is open. The rear end of the barrel hasa chamber communicating with the bore to receive and contain the casingsof rounds of ammunition arranged and fired in the rifle.

Rearward of the barrel and chamber is a breach structure or mechanismprovided to effect the engagement of ammunition into the chamber andbarrel for firing, and for the extraction of the casings of spent orfired ammunition fromthe chamber. A firing mechanism comprising atrigger-controlled firing pin and operable to strike the primer of theammunition to effect detonation and oxidation of the power in theammunition is provided. Firing of the ammunition results in thegenerating of gases which force the bullets from engagement with theircasings, longitudinally through and from the rifled bore of the barrel.

The details of construction, proportioning and configuration of thevarious components of ammunition of the character referred to above aresubject to considerable and wide variations. With few possibleexceptions, the invention here provided is compatible with and can beeffectively related to all commonly used structures, sizes and forms orstyles of ammunition.

In the ordinary use of rifles, there is a tendency for the shells tobecome jammed or to stick in the chambers. The above is due to the factthat when the ammunition is fired, the casings are expanded in thechambers by the gas pressures. The casings are intended to yieldinglyexpand into tight supported engagement in the chamber under the gaspressure generated, as the ammunition is fired and to thereaftercontract from such engagement to permit their easy extraction therefrom.In practice, sufficient contraction does not always occur and thecasings stick in the chambers. This is frequently due to the heatexpansion of the metals defining the chambers and the casings andcommonly occurs during repeated or rapid firing of the rifles.

The above sticking or jamming of casings in the chambers of rifles canbe prevented by the application and/or use of a suitable lubricant inthe chambers and- /or about the casings, but such has been consideredimpractical due to the fact that suitable lubricants tend to be stickyand to collect and carry foreign matter which would bring about far moreserious results than occasional jamming. Further, available lubricantsconsidered suitable for use in firearms are products which tend to burnand break down in such a manner as to foul and gum up the chambers andbores of gun barrels when present in suitable quantity to effectlubrication and when subjected to the temperatures encountered duringthe firing of ammunition.

In the art, at present, it is considered proper and accepted practice tomaintain the chambers and bores of rifles and the ammunition therefor,clean and dry. In those cases where lubricous materials are employed,they are employed primarily as protective coatings to prevent rust andoxidation of the metal surfaces and are preferably light lubricantsapplied as thinly or lightly as is practical.

In the normal use of rifles, the bullets, as they are moved through thebores of the barrels establish sliding bearing engagement on the landsof the helical rifling ribs therein and are caused to rotate thereby.The noted sliding of the bullets on the lands results in a transfer ofmetal of the bullets (which are soft metals such as lead or copper) ontothe surface of the lands and on or at the leading sides of the helicalribs, i.e., the sides of the ribs toward which the bullets advance. As aresult of such transfer of metal, the bore of rifles becomes fouled orleaded up at a rapid rate and must be regularly taken out of service andcleaned. In addition to leading up the barrels, due to the lack ofsuitable lubrication, considerable wearing of the lands or ribs in thebores occurs with the result that a proper fit between bullets and therifling lands is soon lost and accuracy of the firearms rapidlydeteriorates.

In practice, the bore of an Armalite AR 18 rifle should be cleaned afterevery 200 or 300 rounds of ammunition has been fired therethrough and isgenerally worn out and must be replaced after approximately 5,000rounds.

It has long been recognized that if a bore and/or the bullets of rifleammunition .could be effectively lubricated, leading up of the borecould be eliminated and wearing of the bore, that is, wearing of therifling lands could be materially reduced. In spite of the above, due tothe over balancing adverse effects which are experienced in the use oflubricants, such as burning of the lubricants and the resulting buildingup of carbon and varnishes in the chamber and bore, as well as thetransporting of foreign matter picked up by lubricants and carried intothe chamber and bore thereby, it is generally accepted practice to avoidthe use of lubricants and to operate rifles with the chambers, bores andthe ammunition in as dry and clean a condition as is possible, free ofany appreciable and/or effective quantities of lubricant.

In the art of ammunition, there exists a special class of bullets termedtracer bullets, which bullets have cavities entering their rear ends andin which a body of combustible material, such as phosphorous, isdeposited. The combustible material is ignited by the burning powder inthe casings and continues to burn as the bullets travel through the air,creating a visible flame at the rear of the bullet and a trail ofglowing particles and/or gases which can be visually detected orwatched. Withthe use of tracer bullets, one can view the course ofbullets leaving his firearm and can adjust the direction of fireaccordingly and to effect hitting a desired target. Such bulletsconstitute a supplement or substitute for the aiming sights normallyprovided on firearms.

Ordinary tracer bullets have been outlawed for civilian use due to theirincendiary nature and the likelihood that the combustible material theycarry will contact and ignite combustible materials along the paths ofthe bullets. Accordingly, the ordinary tracer bullet is restricted foruse by the military.

As regards military use of tracer bullets, they are hazardous ordangerous to use since while they show the operator of the rifle fromwhich they are fired where the bullets are going, they also show anenemy exactly where the bullets are coming from and expose the positionof the operator.

While some tracer bullets, for large bore weapons, are large enough tocarry a sufficient supply of combustible material so that a smoke trailof sufficient extent and density for daylight viewing is created, suchbullets for small bore weapons or rifles do not leave an adequate trailfor daylight viewing.

Still further, tracer bullets, as now provided by the art, are notconsidered effective or damaging projectiles since they are hollowed outto accommodate the combustible material and are so light when thatmaterial has burned away to any appreciable extent that they loseeffective penetrating power.

As a result of the above, ammunition rounds with tracer bullets arenever used exclusively, but are mixed with a larger quantity of numbersof rounds with regular bullets, in a spaced sequential pattern and areutilized for the purpose of indicating, generally, where the regularbullets, fired sequentially therewith, are going.

Since tracer bullets are different in weight than the regular bulletswith which they are fired and since their weight varies, theirtrajectory is entirely different than the regular bullets, with the endresults that they do not really show where the regular bullets aregoing, but, at best, simply indicate the general direction in which theregular bullets are directed.

A principal object and feature of the present invention is to provide alubricous jacket for bullets which effectively lubricates the bore of arifle from which it is fired to materially extend the bore life thereofand which lubricates the chamber of the rifle to prevent freezing ofcasings therein.

It is an object of this invention to provide a nonincendiary tracerbullet having a jacket composed of materials which vaporize under heatgenerated between the bullet and air to leave a visible vapor trail.

Another object and feature of the instant invention is to provide atracer bullet of the character referred to wherein the material whichvaporizes is such that it will not vaporize until the bullet hastraveled a substantial and predeterminable distance from the rifle and adistance for sufficient heat to be generated by the friction of the airto effect vaporization of said material whereby the vapor trail left bythe bullet is effective to show the operator of the gun where the bulletis directed, but is not such that it will disclose to an enemy or otherswhere the rifle and operator are located.

It is an object and feature of this invention to provide a tracer bulletof the character referred to which is not especially made to hold asupply of combustible material, but which is a regular or normal bulletof normal weight with a substantially normal trajectory and normalimpact and/or penetrating characteristics.

Yet another object and feature of this invention is to provide ajacketed bullet, or a jacket-like coating for bullets, of the characterreferred to which has an exterior surface which is sufficiently hard,smooth, dry and non-sticky that it will withstand normal and reasonablehandling and abuse and will not collect and/or carry foreign matterwhich is apt to cause damage to a rifle in which the bullet is engagedand fired.

An object and feature of my invention is to provide a bullet jacket ofhighly lubricous material, which material, if left or deposited in abore through the bullet is fired, will vaporize cleanly in the presenceof the heat generated in the rifle and is therefor such that it will notburn and leave harmful or undesirable residue in the bore.

An additional object and feature of my invention is to provide a jacketor jacket-like coating of the character referred to which effectivelyprotects the bullet from moisture and which effectively hermeticallyseals the interior of a related casing, about the forward open endthereof adjacent and about the bullet.

It is an object and feature of my invention to provide a jacketstructure or jacket-like coating of the character referred to which isextremely easy and economical to establish and/or apply to ammunition.

The foregoing and other objects and features of my invention will befully understood and will become apparent from the following detaileddescription of the invention throughout which description reference ismade to the accompanying drawings in which:

FIG. 1 is a side elevational view of a round of ammunition embodying myinvention;

FIG. 2 is an enlarged detailed sectional view of the structure shown inFIG. 1, taken as indicated by line 2-2 on FIG. 1;

FIG. 3 is a view illustrating the structure shown in FIG. 2 related tothe chamber and bore of a firearm;

FIG. 4 is a sectional view taken substantially as indicated by line 44on FIG. 3;

FIG. 5 is an elevational view substantially illustrating one state orcondition of the bullet after it leaves a firearm; and

FIG. 6 is a diagrammatic view of a method of establishing my newstructure.

When viewing and considering the drawings, it is to be understood thatthe proportioning of elements, parts and/or portions of the structureillustrated are not necessarily correct and have, where appropriate,been exaggerated so as to better illustrate the invention.

Referring to the drawings, I have shown the invention embodied in and/orwith a standard or conventional round of ammunition A such as is used inmilitary and- /or hunting rifles.

The ammunition round A includes an elongate cylindrical shell or casingC having an open front end 10 and a closed rear end 11, and a projectileor bullet B engaged in the open front end 10 of the casing.

The casing C is a hollow shell-like part established of metal,preferably brass. The rear end portion of the casing is formed toestablish a radially outwardly opening extractor groove 12 and has acentral rearwardly opening recess 14 in which a detonator cap D isengaged. The cap D is hermetically sealed in the recess 14 by theapplication of a suitable sealing compound (not shown) in the recess andabout the cap.

In the drawings and for the purpose of illustrating a preferred form andcarrying out of the invention, I have elected to show the casing C asbeing that form or class of casing which is characterized by a forwardneck portion of reduced diameter to receive and hold or carry the bulletB.

The bullet is an elongate metal projectile having a substantiallystraight cylindrical rear portion and a forwardly convergent cylindricalfront portion 21 terminating at a substantially pointed target or objectengaging front end.

The rear portion 20 of the bullet is of a diameter which permits thatportion of the bullet to be freely slidably engaged in the front portionof the of the casing C, at its open front end 10. The bullet B isreleasably gripped and/or held in the casing by the front edge portion Xof the casing which is suitable crimped, radially inwardly into tightengagement with the rear portion of the bullet.

In the case illustrated, the cylindrical rear portion of the bullet isprovided with an annular, radially outwardly opening groove 25 toreceive and in which the crimped portion or edge X of the casing isengaged.

The groove 25 is dimpled, or, in effect, serrated about itscircumferential extent to define malleable or readily formableprojections which the crimped edge of the casing forms to establish snugand/or or tight mating engagement between the bullet and casing. Whilethe serrated groove 25 in the bullet effects desired engagement with thecrimped edge of the casing, it pre vents the establishment of a moistureproof seal between the bullet and the casing.

In some ammunition, the bullets are ungrooved and are simply pressfitted into the casings to be held thereby, or the casing is crimped toengage the straight cylindrical surfaces of the bullets. In suchstructures, while a seal is more readily established between the bulletsand the casings, any seal which is established is not sufficientlystrong or tight to prevent the movement of moisture between the bulletsand casings, and into the casing.

In FIG. 2 of the drawings, the clearance between the rear portion of thebullet and the forward portion of the casing, rearward of the crimpededge thereof is exaggerated or shown excessive for purposes ofillustration.

The interior of the casing C, rearward of the bullet, is filled withsuitable explosive powder P.

The ammunition round A thus far described is a typical, conventionaltype and/or class of ammunition.

The round A, as shown in FIGS. 3 and 4 of the drawings, is, when used,engaged in the barrel R of a related firearm or rifle with the frontportion of the bullet projecting forwardly from the casing C and enteredin the rear end of a longitudinal bore extending through the barrel. Thefront portion of the casing C is engaged in an enlarged casing receivingchamber 31 at and communicating with bore 30.

The bore 30 is provided with a plurality of circumferentially spacedradially inwardly projecting, longitudinally extending, helical riflingribs 32 with substantially radially inwardly disposed, flat, lands 33.In practice, the lands can, as shown, be inclined planes with respect totheir radial planes whereby they are greater in radial extent alongtheir longitudinal leading edges than along their trailing edges, withrespect to the movement of bullets relative thereto.

The bore 30 is greater in diametric extent than the bullet B and theradial extent of the rifling ribs 32 is such that the lands 33 thereofestablish positive frictional sliding engagement with the rear portionof the bullet B and in such a manner that they turn or rotate the bulletin and relative to the bore 31 as the bullet is moved longitudinallytherethrough.

The extent to which the rifling ribs or lands engage the bullets issufficient to notch and/or score the exterior surface of the bullet,substantially as indicated at Z in FIG. 5 of the drawings.

The chamber 31 is shaped or formed similar to the exterior of the casingC and is slightly larger than the casing whereby casings can be freelyengaged in and extracted or removed from the chamber, but not so largethat when the round is fired and caused to expand, the chamber will notengage and support the exterior of the casing and prevent its rupturing.Accordingly, substantial clearance exists between the surfaces of thechamber and the casing before the ammunition round is fired. When theround is fired, such clearance is substantially eliminated. After theround is fired, the casing, due to the resiliency of the metal,contracts to near its original size and shape. It does not returncompletely to its original size and shape and frequently will remain insufficient partial contact with the chamber to be frictionally held orstuck therein.

The above noted structural and cooperative relationship of theammunition round A and the rifle barrel R is illustrative of a standardor conventional combination and relationship of parts in the art towhich my invention relates and in which or with which my invention canbe advantageously incorporated or related.

The instant invention includes an ammunition round, such as the round Aillustrated in the drawings and described above and in addition theretoand/or in combination therewith, includes a jacket .I on and about theforward portion 21 of the bullet B. The jacket I can continue rearwardlyabout the forward part of the rear portion 20 of the bullet and canfurther extend rearwardly about the forward portion of the casing C.

The jacket J includes a body or inner layer L of soft lubricous materialof substantially uniform thickness on and about the portion of thebullet which the jacket encloses and a hard, dry, frangible outer layer,shell or skin S about the inner lubricous layer L.

The lubricous material is material having excellent lubricatingcharacteristics between bearing metal parts or surfaces and which, undernormal conditions and to temperatures up to at least 200 F is a stable,non-fluid or solid material. It is sufficiently plastic that it will,under appreciable applied force readily flow. Further, the material ofthe layer L is such that when it is heated to, for example, 500 F. to700 F it vaporizes.

It is important that the material of layer L vaporizes at a temperaturewell below that temperature where it will burn and so that it will notcarbonize or and/or leave appreciable deposits of carbon and/orvarnishes on heated surfaces with which it comes into contact.

The lubricous layer L is established of hydrogenated, organic oil, suchas vegetable oil.

In the process of hydrogenating organic or vegetable oils, that is, inthe process of scrubbing and mixing such oil with hydrogen gas, theviscosity of the oil is increased to an extent that it becomes non fluidand is in a plastic solid state. Further, the range of temperatures atwhich the oil will liquify vaporizes and burn is increased or elevated.

In carrying out of my invention, the solid, plastic, hydrogenatedvegetable oil is hydrogenated to an extent where its burning temperatureis well below and its melting and vaporizing temperatures are within therange of temperatures encountered in the bore and chamber of a gun andwithin the range of temperatures generated by the friction between thebullet and the air as the bullet travels therethrough.

When such oil is hydrogenated to within the temperature range indicatedabove, the viscosity is quite high and it is in a rather hard or stillplastic state.

In addition to the above hydrogenated oil, the layer L includes a binderof Carnuba wax which serves to further stiffen the hydrogenated oil. Inpractice, the layer L can contain or include approximately /4hydrogenated vegetable oil and A carnuba wax. Carnuba wax, in a purestate, is a hard, extremely brittle material with a vaporization pointnear l,OO F., and is generally considered to be totally inappropriate asa lubricant and an incompatible, if not a deleterious substance for usein firearms.

It has not been determined What molecular, grain and/or crystallinestructure the noted oil and wax mixture creates, but the material isquite hard, stiff and wax-like. It is a considerably stiffer and hardermaterial than the hydrogenated oil alone. Further, when the oil isvaporized, the carnuba wax is apparently vaporized with it or is presentin such finely divided particles that it is effectively carried away bythe vaporized oil. If traces of the wax are left and are to be found inthe barrel and/or chamber of a gun in which the ammunition A is fired,it is in such small quantities and in such a fine state that it issubstantially non-detectable and insufficient to cause any adverseeffects.

The outer layer or skin S of the jacket structure J is a hard, dry,thin, frangible layer or skin of carnuba wax. The skin S is sufficientlyhard, dry and tough that it does not pick up and carry foreign matter,and is not subject to being penetrated or broken down to an appreciableextent through ordinary handling. It is sufficiently hard and tough orstrong so that when it is related to or combined with the layer L andwhen normal effort is exercised to remove the jacket J from a relatedbullet, one must engage the jacket with a rather hard, sharp orfine-edged object, such as his fingernail, and scrape the jacket freefrom the bullet with deliberately applied and directed force.

The layers L and S of the jacket J are established and applied to thebullet B and casing C of the ammunition round A by dipping and removingthe bullet end of the round into and from a body of heated molten, oiland wax mixture.

After the bullet is dipped and the mixture clinging thereto cools, thecarnuba wax at the exterior of the coating and which has a highermelting point than the oil, solidifies first, coalescing with other ofsaid wax adjacent to the surface to create the thin, hard, frangibleskin S.

The skin S is extremely thin, is hard and is frangible. The skin S issuch that when it is forcibly acted upon, it breaks up in such a mannerthat it cannot be readily segregated from the material of the layer Lwhich is forcibly acted upon therewith and, like that wax within the oilof the layer L, is carried away by the oil when the oil is vaporized.

The skin S is extremely thin and need only be sufficiently thick toprovide the inner layer L with a dry, impervious skin which isnon-sticky and on which foreign matter will not stick to foul theammunition.

In practice, and as illustrated in FIG. 6 of the drawings, the bullet Bof the round A is dipped in the hot molten mixture up to the front endof the casing C. Capillary attraction causes the molten material to flowup about the casing about inch.

The molten mixture is at about 300 F. (below the cook-off temperature ofthe ammunition which is about 350 F.) The dip period is sufficient toheat the round enough to drive the moisture ladened air from theinterior of the shell. (This can be detected by bubbles escaping frombetween the casing and bullet).

When the round is extracted from the oil and wax and is cooled, theportion of the jacket about the open front end of the casinghermetically seals the casing.

When ammunition round A, as provided by the present invention, isadvanced into engagement in the chamber 31 and bore 30 of a relatedbarrel R, the portion of the jacket J about the rear portion of thebullet is engaged by the rifling ribs 32 in the bore and is displacedthereby, lubricating the ribs and tending to deposit certain of thematerial of the jacket in the chamber. The portion of the jacket aboutthe forward end of the casing occurring in the chamber combines withthat material that is displaced therein by the rifling ribs (if any).(See FIGS. 3 and 4 of the drawings).

When the round is fired, the casing expands and the material of thejacket in the chamber is displaced in the chamber and about the casingand in such a way as to effectively lubricate the chamber and the casingand to prevent the casing from sticking in the chamber.

The heat generated by the burning of the powder heats the casingsufficiently to vaporize the lubricous material and to such an extentthat it rapidly disappears. As the lubricant vaporizes and disappears,it carries with it considerable heat, with the result that the rifle orgun heats less than a gun firing conventional ammunition.

As the bullet B is forced longitudinally through and from the bore 30 ofthe barrel R, the jacket material lubricates the lands 33 of the riflingribs 32. The heat of the expanding burning powder and gases vaporizesthe jacket material deposited or left in the barrel and it has beendetermined that the vaporized material tends to pick up ash or residuefrom the powder and to carry it out of the barrel as it vents therefrom.

In a test made with my new ammunition, 600 rounds were fixed in time andrapid fire groups in and from an Armalite AR 18 rifle. The bore of therifle was, prior to the commencing of the test, dirty and in need ofcleaning. Following the test, the barrel was clean and not in need ofcleaning.

In the 600 rounds fired, not one round of ammunition became stuck in thegun, despite the fact that every effort was made to create those firingconditions where jamming, due to excessive heating of the rifle,normally occurs.

When the bullet leaves the front or muzzle end of the barrel, the jacketJ on the forward tapered portion thereof and which is not engaged by therifling ribs, remains in tack, substantially as indicated in FIG. 5 ofthe drawings.

As the bullet travels through the air, friction heat is generated whichheat is conducted through the skin S to the layer L. As the heatincreases, the material of the layer L vaporizes leaving a visible trailbehind the bullet.

The heat which vaporizes the jacket material left on the bullet B afterit leaves the bbarrel of the gun does not build up sufficiently tovaporize the material until it has traveled a substantial distance.

In practice, and by varying the heat range of the jacket material, itcan be made so that it will commence to vaporize when it reaches acertain distance from the gun and where an anticipated or knowntemperature will be generated. For example, it can be made to vaporizewhen the bullet is about 25, 50, 75 or 100 yards from the muzzle of thegun.

The vapor trail left by the jacket J is substantially white, dense andvisible.

By varying the thickness of the jacket, the denseness of the trail andits potential length can be varied as desired.

In practice, by varying or changing the period of dipping to establishthe jacket, its thickness can be effectively varied and its thicknessthroughout its longitudinal extent can be varied. For example, thethickness of the jacket at the front portion of the bullet can be madethicker than the rear portion of the jacket. The front portion of thejacket might be 1 /2 mils and the rear portion thereof /2 mil inthickness. or the entire jacket may be established at /2 or 1 mil inthickness, as desired or as circumstances require.

The principal advantage to be found in the use of my new ammunitionround is the extention of bore life. Anticipated bore life through useof my new ammunition is at best two times and in many instances three ormore times the anticipated bore life if conventional ammunition is used.

The second most important advantage found in the use of my newammunition is lubrication of the chamber which effectively preventsfreezing or jamming of casings in the chamber.

The other advantages to be found in and by the use of my new ammunition,such as the tracer effect afforded and other advantages not specificallymentioned are generally of secondary significance though such advantagesare or can be of primary importance when and in those situations wheresuch advantages are particularly sought to be attained.

Having described my invention, I claim:

1. Self-lubricating vapor-trailing ammunition round for use in abarreled firearm, comprising an elongate, cylindrical, hollow casingwith an open front end and a closed rear end, an elongate bullet with asubstantially straight cylindrical rear portion engaged in the openfront end of the casing and a forwardly convergent front portionprojecting forwardly from the casing,

explosive power within the casing, detonator means at the rear end ofthe casing, and a jacket having an inner layer of hydrogenated vegetableoil on and about the forward portion of the round, a thin and outer skinof normally dry, hard frangible wax, said vegetable oil beinghydrogenated to that extent where it vaporizes at that range oftemperatures generated by the friction between the bullet and ambientair after the round has been detonated in a related barreled firearm andthe bullet leaves the barrel thereof.

2. A structure as set forth in claim 1 wherein the jacket is coextensivewith the front portion of the bullet.

3. A structure as set forth in claim 1 wherein the jacket is coextensivewith the portion of the bullet extending forwardly from the casing.

4. A structure asset forth in claim 1 wherein the jacket is coextensivewith the portion of the bullet extending forwardly from the casing andextends rearwardly therefrom about the forward portion of the casing toseal between the bullet and the casing and to lubricate a chamber in thefirearm in which the casing is engaged.

5. A structure as set forth in claim 1 wherein the thin, hard and dry,frangible outer skin is established of carnauba wax and has a highermelting point than the vegetable oil.

6. A structure as set forth in claim 1 wherein the wax establishing theouter skin extends into the inner layer of hydrogenated vegetable oil toreinforce and contain said layer.

7. A structure as set forth in claim 6 wherein said jacket structurecomprises about three-quarters hydrogenated vegetable oil andone-quarter carnuba wax.

8. A structure as set forth in claim 6 wherein the jacket is coextensivewith the front portion of the bullet.

9. A structure as set forth in claim 7 wherein the jacket is coextensivewith the front portion of the bullet.

10. A structure as set forth in claim 9 wherein the jacket iscoextensive with the portion of the bullet extending forwardly from thecasing and extends rearwardly therefrom about the forward portion of thecasing to seal between the bullet and the casing and to lubricate achamber in the firearm in which the casing is engaged.

1. Self-lubricating vapor-trailing ammunition round for use in abarreled firearm, comprising an elongate, cylindrical, hollow casingwith an open front end and a closed rear end, an elongate bullet with asubstantially straight cylindrical rear portion engaged in the openfront end of the casing and a forwardly convergent front portionprojecting forwardly from the casing, explosive power within the casing,detonator means at the rear end of the casing, and a jacket having aninner layer of hydrogenated vegetable oil on and about the forwardportion of the round, a thin and outer skin of normally dry, hardfrangible wax, said vegetable oil being hydroGenated to that extentwhere it vaporizes at that range of temperatures generated by thefriction between the bullet and ambient air after the round has beendetonated in a related barreled firearm and the bullet leaves the barrelthereof.
 2. A structure as set forth in claim 1 wherein the jacket iscoextensive with the front portion of the bullet.
 3. A structure as setforth in claim 1 wherein the jacket is coextensive with the portion ofthe bullet extending forwardly from the casing.
 4. A structure as setforth in claim 1 wherein the jacket is coextensive with the portion ofthe bullet extending forwardly from the casing and extends rearwardlytherefrom about the forward portion of the casing to seal between thebullet and the casing and to lubricate a chamber in the firearm in whichthe casing is engaged.
 5. A structure as set forth in claim 1 whereinthe thin, hard and dry, frangible outer skin is established of carnaubawax and has a higher melting point than the vegetable oil.
 6. Astructure as set forth in claim 1 wherein the wax establishing the outerskin extends into the inner layer of hydrogenated vegetable oil toreinforce and contain said layer.
 7. A structure as set forth in claim 6wherein said jacket structure comprises about three-quartershydrogenated vegetable oil and one-quarter carnuba wax.
 8. A structureas set forth in claim 6 wherein the jacket is coextensive with the frontportion of the bullet.
 9. A structure as set forth in claim 7 whereinthe jacket is coextensive with the front portion of the bullet.
 10. Astructure as set forth in claim 9 wherein the jacket is coextensive withthe portion of the bullet extending forwardly from the casing andextends rearwardly therefrom about the forward portion of the casing toseal between the bullet and the casing and to lubricate a chamber in thefirearm in which the casing is engaged.